This invention relates to prevention of ice build-up at the intake end of air scoops or similar devices for feeding air to internal combustion engines for jet prop powered aircraft and the like.
The leading edges of aircraft wings and other components are subjected during certain flight conditions to the tendency of build-up of relatively thick layers of ice which add considerable weight to the aircraft, interfere with the air foil configuration of the wings and other components, and reduce speed and thus efficiency of the aircraft. Under extreme conditions the ice may render the aircraft incapable of flight. Whether the aircraft is powered by a piston type internal combustion engine or by a jet engine, either full jet or jet prop, there is a necessity to feed air to the engine for mixing with the fuel to form a combustible mixture. Subsequent to combustion, the expanding products of combustion function to drive the pistons and thus the propeller connected to the engine or in a pure jet powered aircraft, force the aircraft to move forwardly by a reaction to the expanding gases as they are discharged rearwardly of the aircraft engine.
Conventionally, an elongated air scoop forming a projection of the aircraft fuselage, wing or other component and projecting into the air stream is employed in supplying air to the engine. The open forward end of the scoop collects air passing at high speed over the aircraft and the scoop directs the air to the air intake of the engine proper. Ice in building up on the leading edge of the air scoop, interferes with the capability of the air scoop to feed air to the engine and, of course, weighs down the aircraft.
Attempts have been made to incorporate a defrost system to such air scoops by providing an electric boot integrated to the scoop at the inlet end. Such boots may include an electric resistance heater functioning to maintain an exterior temperature to the boot sufficient to melt any ice built up on such surface. Such arrangements have been complicated and expensive and have not performed to full satisfaction.